Alcohol Consumption and Body Mass Index: AlcoholFood Competition or Third-Variable Problem?
Jenna R. Cummings & A. Janet Tomiyama
Department of Psychology, University of California, Los Angeles
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Alcohol-food competition framework posits
that alcohol and food cannot simultaneously
activate reward pathways à individuals tend
to consume one substance to the exclusion of
the other1.
In support, studies consistently document an
inverse relationship between alcohol
consumption and Body Mass Index (BMI)2-4.
However, this research is limited in two
respects:
1.  The inverse relationship has only
been documented cross-sectionally.
2.  In these studies BMI is used as a
proxy for actual caloric intake.
The current study examined the longitudinal
relationship of alcohol intake to both BMI
and directly examined caloric intake.
Data obtained via the National Heart,
Lung, and Blood Institute Growth and
Health Study.
Sample of 2,379 Black (n = 1,213) and
White (n = 1,166) adolescent girls
assessed yearly from age 15 to 19.
At annual visits, anthropometric and
consumption behavior data was collected:
1.  Alcohol intake à During the past 30
days, on how many days did you have
at least one drink of alcohol?
2.  Caloric intake à 3-day daily food
diary recording all food and drink,
excluding alcohol.
3.  BMI à calculated using the standard
formula (weight[kg]/height[m]2).
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Measured covariates: Race, household
income, parental education, and age of
menarche.
Age 16
Age 17
Age 17
Age 18
Alcohol
Consumption
Age 19
Alcohol
Consumption
Age 19
-0.10**
Alcohol
Consumption
Age 15
Alcohol
Consumption
Age 16
BMI
Age 19
-0.05
-0.06*
-0.11
0.11
0.07
Total Food
Consumption
Age 16
BMI
Age 15
Age 16
Age 17
Age 18
CFI = 0.92, RMSEA = 0.10
Total Food
Consumption
Age 19
Age 17
CFI = 0.97, RMSEA = 0.04
Multivariate growth models between alcohol intake and BMI, and alcohol and caloric intake. Covariance pathways within these variables’ intercepts and slopes represented by gold lines.
Longitudinal relationships between study variable represented by blue lines. Alcohol intake and BMI increased at mean-level over five years, but caloric intake remained stable. This is
illustrated by steep versus flat arrows. Standardized values reported. CFI = Comparative Fit Index, RMSEA = Root Mean Square Error of Approximation. * p < .05, ** p < .01, *** p < .001.
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Alcohol Intake and BMI:
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Alcohol Intake and Caloric Intake:
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The estimates of slope for alcohol consumption and
BMI were significantly negatively associated.
Further, a significant negative prospective
association between the estimates of intercept for BMI
and slope for alcohol intake emerged.
The estimates of slope for alcohol consumption and
total calories and sugar consumption were not
significantly associated.
Neither were prospective relationships between
intercepts and slopes.
BMI, in this context, is not an appropriate proxy for
caloric intake.
Rather than alcohol-food competition within an
individual, third variables are likely driving the inverse
relationship between alcohol intake and BMI.
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Future work can examine alternative explanations:
1.  Metabolism could confer an individual with
both a lean BMI and higher tolerance to
alcohol.
2.  Given that individuals commonly drink
alcohol as a part of social functions, those
with higher BMIs may experience weight
discrimination and be less likely to attend
social functions and drink alcohol.
References:
1Gearhardt, & Corbin (2009). Body mass index and alcohol consumption: Family
history of alcoholism as a moderator. Psychology of Addictive Behaviors, 23(2), 216–25.
2Colditz, Giovannucci, Rimm, Stampfer, Rosner, Speizer, Willett (1991). Alcohol intake
in relation to diet and obesity in women and men. The American Journal of Clinical
Nutrition, 54(1), 49–55.
3Gearhardt, Harrison, & McKee (2012). Does co-morbid depression alter the inverse
relationship between obesity and substance use disorders? Drug and Alcohol
Dependence, 124(1-2), 185–8.
4Kleiner, Gold, Frost-Pineda, Lenz-Brunsman, Perri, & Jacobs (2004). Body mass index
and alcohol use. Journal of Addictive Diseases, 105–118.